The invention relates to a disc brake, preferably pneumatically actuated, in particular for a motor vehicle, having a brake disc with a brake disc axis, a brake caliper, in particular a sliding caliper, with an application section and a caliper back, which are connected via tension struts, and at least two brake pads each having a brake pad carrier. The invention is also concerned with a brake caliper and a brake pad set.
Vehicles and certain technical equipment often use friction brakes to convert kinetic energy. The disc brake is preferred here, especially in the passenger car and commercial vehicle sectors. With the typical design of a disc brake, the disc brake comprises a brake caliper together with an internal mechanism, as well as two brake pads and the brake disc. Forces are introduced to the internal mechanism via a power source, for example via a pneumatically actuated cylinder, are multiplied by an eccentric mechanism and are transmitted as an application force to the brake pads and brake disc via threaded tubes, which are also referred to as threaded plungers, threaded spindles, pressure plungers or the like, together with pressure pieces. The wear on the brake disc and the brake pads is compensated by way of the threaded tubes.
A clearance between the brake pads and the brake disc is referred to as a release clearance. The retardation is significantly affected by the friction coefficient between the brake disc and the brake pad. Since the pads are designed as wearing parts and the friction coefficients are dependent on the rigidity, these pads are generally softer than the brake disc, i.e. the pads undergo a change in pad thickness over their time in use: they wear. Owing to this pad wear and additional disc wear, the release clearance increases. This change in pad thickness gives rise to the need for wear readjustment to compensate for the change and thus establish a constant release clearance.
One example of a readjustment device is described in DE 10 2004 037 771 A1.
The application forces act via two brake pads on the brake disc which, depending on the magnitude of the application force, undergoes a retardation of the rotational movement. The brake pad which lies on the application side of the brake disc is referred to as the application-side brake pad. The other brake pad is located on the other side of the brake disc and is in contact with a caliper back of the brake caliper. During a braking operation, the application-side pad is moved in the direction of the brake disc. As soon as the pad is in contact with the brake disc, the brake caliper is moved by the resulting counterforce in the direction of the brake disc together with the back-side brake pad. If the back-side brake pad now also comes into contact with the brake disc, a braking action is produced.
The back-side brake pad lies against the caliper back of the brake caliper by way of a face-milled surface. This surface is approximately in the shape of the back-side brake pad. The application-side brake pad is pressed against the brake disc, for example via two threaded tube units. It has been found disadvantageous in this case that an uneven wear of the brake pads may arise here.
It is therefore the object of the present invention to provide an improved disc brake.
It is a further object to provide an improved brake caliper.
It is yet another object to provide an improved brake pad set.
These and other objects are achieved by a disc brake, by a brake caliper, and by a brake pad set in accordance with embodiments of the invention.
A disc brake according to the invention, preferably pneumatically actuated, in particular for a motor vehicle, comprises a brake disc with a brake disc axis, a brake caliper, in particular a sliding caliper, with an application section and a caliper back, which are connected via tension struts, and at least two brake pads each having a brake pad carrier. Of the brake pads, an application-side brake pad is assigned to the application section, and a back-side brake pad is assigned to the caliper back. The brake pad carrier of the back-side brake pad and the caliper back of the brake caliper are in contact via at least one pair of contact surfaces. One contact surface of the at least one pair of contact surfaces is an end surface of a projection, and the other contact surface of the at least one pair of contact surfaces is a bottom surface of a recess.
By way of this design, configuration and arrangement of contact surfaces between the back-side brake pad and the caliper back of the brake caliper, uneven wear of the brake pads is significantly reduced.
In one embodiment, the projection with the one contact surface of the at least one pair of contact surfaces and the recess with the other contact surface of the at least one pair of contact surfaces correspond with each other and interact with each other in a form-fitting manner in the installed state. The projection is accommodated in the recess, as a result of which the back-side brake pad is advantageously prevented from unscrewing from the brake caliper.
The projection with the one contact surface of the at least one pair of contact surfaces and the recess with the other contact surface of the at least one pair of contact surfaces can have a circular cross section. As a result, the recess can be produced in a simple manner, for example by drilling and/or hollowing out by turning.
Alternatively, the projection with the one contact surface of the at least one pair of contact surfaces and the recess with the other contact surface of the at least one pair of contact surfaces can have an oval or polygonal cross section. This affords the advantage that a risk of confusion is reduced by means of this unambiguous assignment.
In a further embodiment, the projection with the one contact surface of the at least one pair of contact surfaces is integrally formed on the caliper back of the brake caliper, and the recess with the other contact surface of the at least one pair of contact surfaces is molded into the brake pad carrier of the back-side brake pad. A weight savings is thereby achieved. In addition, the outlay on producing the projections on the caliper back, for example by milling work, is not more complicated in comparison to a conventional face-milled contact surface.
The projection with the one contact surface of the at least one pair of contact surfaces protrudes on the caliper back of the brake caliper from a machined free surface in the direction of the brake disc. The free surface which is produced permits a weight savings.
In a further embodiment, the disc brake furthermore has an application device, preferably with a pivoted brake lever, and at least one threaded tube unit having at least one threaded tube with a center axis. The projection with the one contact surface of the at least one pair of contact surfaces and the recess with the other contact surface of the at least one pair of contact surfaces are arranged with respect to each other coaxially with respect to the center lines thereof and coaxially with respect to the center axis of the at least one threaded tube unit. In this manner, an unfavorable leverage effect is not produced on the back-side brake pad during a braking operation, and therefore uneven wear is significantly reduced.
In an alternative embodiment, the disc brake furthermore has an application device, preferably with a pivoted brake lever, and at least two threaded tube units each having at least one threaded tube with a respective center axis. A first projection with the one contact surface of the at least one pair of contact surfaces and a first recess with the other contact surface of the at least one pair of contact surfaces are arranged with respect to each other coaxially with respect to the center lines thereof and coaxially with respect to the center axis of the one of the at least two threaded tube units, and a second projection with the other contact surface of the at least one pair of contact surfaces and a second recess with the other contact surface of the at least one pair of contact surfaces are arranged with respect to each other coaxially with respect to the center lines thereof and coaxially with respect to the center axis of the other of the at least two threaded tube units. The two individual contact surfaces are arranged in the same center axes as those of the threaded tube units on the application side. This affords the advantage of a reduction in lever arms in the caliper back with respect to tension struts of the brake caliper. Uneven wear of the brake pads is advantageously significantly reduced.
In yet another embodiment, the disc brake has a readjustment device which is inserted into a threaded tube. A compact construction is therefore made possible.
A brake caliper according to the invention of the above-described disc brake has a caliper back with a transverse section which extends parallel to the brake disc and at a right angle to the brake disc axis. On the side which faces the brake disc, the transverse section has a contact section carrier with at least one projection with the one contact surface of the at least one pair of contact surfaces.
A brake pad set according to the invention for the above-described disc brake has at least one application-side brake pad and at least one back-side brake pad, wherein the back-side brake pad has at least one recess for receiving a projection corresponding to the at least one recess.
In another embodiment, the brake pad set furthermore comprises a pad retaining clip, wherein the at least one application-side brake pad and the at least one back-side brake pad are each provided with a pad retaining spring. Simple installation and simple holding are therefore possible.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.